Bring back naming convention attribute

Author: kristiker

Element.cs

@@ -27,7 +27,7 @@ public class Element : AttributeList, IEquatable<Element>
         /// <param name="name">An arbitrary string. Does not have to be unique, and can be null.</param>
         /// <param name="class_name">An arbitrary string which loosely defines the type of Element this is. Cannot be null.</param>
         /// <exception cref="IndexOutOfRangeException">Thrown when the owner already contains the maximum number of Elements allowed in a Datamodel.</exception>
-        public Element(Datamodel owner, string name, Guid? id = null, string classNameOverride = "")
+        public Element(Datamodel owner, string name, Guid? id = null, string? classNameOverride = null)
             : base(owner)
         {
             ArgumentNullException.ThrowIfNull(owner);
@@ -174,18 +174,13 @@ internal set
             foreach (var property in type.GetProperties(BindingFlags.Public | BindingFlags.Instance))
             {
                 // Check if the property is an auto-property and is declared by a subclass of Element
-                var declaringType = property.DeclaringType;
+                var declaringType = property.DeclaringType!;
 
-                if(declaringType is null)
-                {
-                    throw new InvalidOperationException("Declaring type is null");
-                }
-
-                if (property.GetIndexParameters().Length == 0 && declaringType.IsSubclassOf(typeof(Element)))
+                if (declaringType.IsSubclassOf(typeof(Element)))
                 {
                     var name = property.Name;
+                    name = declaringType.GetCustomAttribute<Format.AttributeNamingConventionAttribute>()?.GetAttributeName(name, property.PropertyType) ?? name;
                     name = property.GetCustomAttribute<Format.DMProperty>()?.Name ?? name;
-
                     properties.Add((name, property));
                 }
             }

Format/Attribute.cs

@@ -3,6 +3,61 @@
 
 namespace Datamodel.Format;
 
+/// <summary>
+/// Subclass this attribute to define a custom attribute name convention.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
+public abstract class AttributeNamingConventionAttribute : System.Attribute
+{
+    public abstract string GetAttributeName(string propertyName, Type propertyType);
+}
+
+/// <summary>
+/// This class' property names are mostly lowercase.
+/// </summary>
+public class LowercasePropertiesAttribute : AttributeNamingConventionAttribute
+{
+    public override string GetAttributeName(string propertyName, Type _)
+        => propertyName.ToLower();
+}
+
+/// <summary>
+/// This class' property names are mostly camelCase.
+/// </summary>
+public class CamelCasePropertiesAttribute : AttributeNamingConventionAttribute
+{
+    public override string GetAttributeName(string propertyName, Type _)
+        => char.ToLowerInvariant(propertyName.AsSpan()[0]) + propertyName[1..];
+}
+
+/// <summary>
+/// This class' property names are mostly m_hungarian.
+/// </summary>
+public class HungarianPropertiesAttribute : CamelCasePropertiesAttribute
+{
+    public override string GetAttributeName(string propertyName, Type propertyType)
+    {
+        var typeAnnotation = propertyType switch
+        {
+            _ when propertyType == typeof(int) => "n",
+            _ when propertyType == typeof(float) => "fl",
+            _ when propertyType == typeof(bool) => "b",
+            _ when propertyType == typeof(Vector2) => "v",
+            _ when propertyType == typeof(Vector3) => "v",
+            _ when propertyType == typeof(Vector4) => "v",
+            _ when propertyType == typeof(Matrix4x4) => "mat",
+            _ => string.Empty,
+        };
+
+        if (typeAnnotation == string.Empty)
+        {
+            return "m_" + base.GetAttributeName(propertyName, propertyType);
+        }
+
+        return "m_" + typeAnnotation + propertyName;
+    }
+}
+
 [AttributeUsage(AttributeTargets.Property, Inherited = true, AllowMultiple = false)]
 public sealed class DMProperty : System.Attribute
 {